A research company has reported it had cloned the first human embryo, a development it said was aimed at producing genetically matched replacement cells for patients with a wide range of diseases.
But the news from Advanced Cell Technology of Worcester, Mass., drew swift protests from religious and political leaders who saw it as a step toward cloning human beings.
Several states, including California, have banned human cloning, and Congress is considering such a ban. But company officials insisted their work is the first step in providing hope for people with spinal injuries, heart disease and other ailments.
``These are exciting preliminary results,'' said Dr. Robert P. Lanza, one of the researchers at Advanced Cell Technology. ``This work sets the stage for human therapeutic cloning as a potentially limitless source of immune-compatible cells for tissue engineering and transplantation medicine.''
Lanza and the company's top executive Michael West said they had no interest in transplanting such early embryos into a woman's womb to give birth to a cloned human being, nor was it clears that their embryo would be capable of that.
But the Washington DC-based National Right to Life Committee wasted little time attacking the announcement.
``This corporation is creating human embryos for the sole purpose of killing them and harvesting their cells,'' said the group's legislative director Douglas Johnson. ``Unless Congress acts quickly, this corporation and others will be opening human embryo farms.''
And a critic of the company who used to sit on ACT's ethics board said Advanced Cell's announcement was premature and would serve only to encourage such harsh reaction against cloning.
Glenn McGee, a University of Pennsylvania bioethicist who resigned from Advanced Cell Technology's ethics advisory board, called the announcement ``nothing but hype.'' He said the company's report lacks any significant details, including what cells company scientists actually grew from the cloned embryo. ``They are doing science by press release,'' he said.
A second company quickly claimed that it had also cloned human embryos, but in unpublished research. The company, Clonaid, said it hopes to eventually create fully developed human clones.
The company keeps its laboratory location secret, citing security concerns. Boisselier said that the embryos were created by injecting eggs with a variety of other cells, but she refused to give details.
In findings published by the online journal, e-biomed: The Journal of Regenerative Medicine, and also described online in Scientific American, the ACT scientists said they had grown a six-cell human embryo.
They said they created the early embryo by injecting a very small cell with its genetic material into a woman's donated egg. In such cloning, the injected DNA often comes from a skin cell, but the researchers this time used a cumulus cell, which nurtures a developing egg.
This technique could produce replacement cells only for a woman of childbearing age, since the injected DNA comes from a woman's reproductive system. However, the scientists have been experimenting with injecting adult skin cells into the eggs as well.
In a separate experiment, the scientists showed they could push the development of human egg cells even further with a technique known as parthenogenesis. In that process, they said, six eggs reprogrammed themselves to develop into early embryos. Such eggs would be largely compatible with the genetics of the egg donor. The scientists described all the work as preliminary. Neither experiment has yet produced the coveted stems cells, master cells which grow into all kinds of body tissues.
Other research groups in this country and abroad have plunged into efforts for human ``reproductive cloning,'' which aims to produce a new person, or ``therapeutic cloning,'' which seeks only to create embryos that would yield stem cells for treating diseases.
And last September, a report from the National Academy of Sciences -- an independent, congressionally chartered organization -- said therapeutic cloning should be pursued.
Dr. Norman Fost, director of the bioethics program at the University of Wisconsin-Madison, said he believes a ``slippery slope'' argument for banning therapeutic cloning is a poor approach.
One could have made such a case against test-tube fertilization, which has turned out to be beneficial, and which also can be seen as a step toward cloning humans, he said.
The announcement by the Massachusetts researchers, he said, is ``a basic part of making stem cell research useful for human beings.'' That, he said is ``a path which the huge majority of the American people favor.''
The researchers described their work as an important step toward producing stem cells to generate replacement cells as treatments for diabetes, heart disease, spinal injuries, and many other ailments. But using human embryos for such work faces huge hurdles in Washington.
``The president has made it clear that he is opposed to any type of human cloning,'' said White House spokeswoman Jennifer Millerwise. ``He supported the House legislation to ban human cloning that passed overwhelmingly. The Senate has a busy calendar but this shows why it is important for the Senate to act.''
Carl Feldbaum, president of the Biotechnology Industry Organization, predicted that Congress would ultimately allow human cloning for therapeutic purposes. ``Therapeutic cloning has been gaining allies as its applications are understood,'' he said.